Commercially available 3D printers, such as the ProJet™ 3D Printers manufactured by 3D Systems of Rock Hill, S.C., use inks, which are also known as build materials, that are jetted through a print head as a liquid to form various 3D objects or parts. Other 3D printing systems also use an ink that is jetted through a print head. In some instances, the ink is solid at ambient temperatures and converts to liquid at elevated jetting temperatures. In other instances, the ink is liquid at ambient temperatures.
To form printed articles, some inks require curing following jetting and deposition of the ink on a surface. Curing can be an exothermic process, and the release of thermal energy during curing can limit the printing speed. In particular, printing and curing ink layers too quickly can result in elevated temperatures at the deposition surface, which can in turn lead to a reduced viscosity of the deposited ink and a concomitant loss of printing resolution due to excessive flow of the ink. In addition, some inks that exhibit high viscosities at ambient temperatures also exhibit phase segregation of ink components over time, including during storage of the ink and/or after the ink is formed into a printed article. For example, in some instances, a pigment and/or a wax component of the ink undergoes settling and/or phase segregation.
Therefore, there exists a need for improved inks for 3D printing, including for rapid and/or pigmented 3D printing applications.